This invention relates generally to techniques for constructing fiber optic sensor arrays, particularly fiber optic hydrophone arrays. Still more particularly, this invention relates to techniques for constructing towed and bottom fiber optic hydrophone arrays.
A towed array generally includes hydrophones and telemetry couplers spliced together and packaged loosely within a foam body, which is then placed within a strength member frame and booted within a hose. For bottom arrays, integration occurs by cutting into a pre-fabricated cable and, once integrated, the hydrophones and telemetry couplers are overmolded for protection.
Generally, for both approaches, the optical fiber used between hydrophones and telemetry components is either tight buffered, in a loose tube (loose buffered), or has the standard thin acrylate buffering. This makes them tend to be susceptible to damage, especially at either splice locations or at transition points from the outer jacketing to the bare fiber.
A fiber optic array cable according to the present invention comprises a plurality of constituent cables that include an optical fiber, a strength member connected to the optical fiber to provide tensile strength and a jacket surrounding the optical fiber and the strength member. A harness is arranged to enclose the plurality of constituent cables securely.
The strength member preferably comprises a plurality of metal strands layered around the optical fiber.
The fiber optic array cable may further comprise at least one breakout connected to selected constituent cables and arranged to contain array components while maintaining the tensile strength provided by the strength member in each optical fiber to which array components are connected.
The breakout preferably includes a base and a pair of end caps connected to the base. Cable terminators are connected to selected constituent cables and anchored in the end caps to maintain tensile strength.
The constituent cables preferably include fiber optic hydrophone leads and leads for connection to telemetry components in a fiber optic hydrophone array.